CLONING, EXPRESSION AND FUNCTIONAL-ROLE OF XRPFI ALPHA-SUBUNITS AND BETA-SUBUNITS IN XENOPUS-LAEVIS OOCYTE

The cDNAs coding for the alpha and beta components of XrpFI, an activa tor of ribosomal protein genes transcription, were isolated. RNA analy sis showed that transcripts of the beta genes are present at constant level throughout Xenopus development unlike the beta proteins which ar e undetectable in the early stages of embryogenesis when transcription is silent. On the contrary, a transcripts and proteins were found in all the embryo stages examined. The role of the XrpFI a and beta subun its in rp-gene transcription has been studied by mRNA microinjection i nto X.laevis oocytes. The presence of the beta subunit appears to be c ritical for the proper rp-gene promoter function. (C) 1995 Academic Pr ess, Inc.